With the changes in the life condition and living environment, human is experienced a greatly improved health level, infectious diseases are being or have been replaced by modern diseases, and the medical model of the human being is being changed from the mere treatment of the diseases to a combination of treatment, prevention, healthcare and rehabilitation. In addition, various alternative medicines and traditional medicines play an increasing role and the concept of “returning to nature” becomes very popular in world wide, and thus the natural drugs from green plants are paid more and more attention due to their high safety, unique pharmacological and physiological activities.
Modern medicinal research on ginkgo leaves is doubtless one of the highlights in the development of natural plant medicines. In early 70s, a rigorously standardized ginkgo biloga extract named EGb761, which is a mixture of flavonol glycosides (its content is 24% or more) and terpene lactones (sum of ginkgolides and bilobalides, the total content is 6% or more), was first produced in large scale by solvent extraction method in Germany, whereby a single phytomedicine with significant and stable therapeutic effects for cardiovascular and cerebrovascular diseases was developed and became the best-selling drug in Europe and attracted much attention in international medical and pharmaceutical domain (K. Chandrasekaran, Z. Mehrabian, B. Spinnewyn, K. Drieu, G. Fiskum, Brain Res. 922 (2001): 282). However, with extensive research, numerous pharmacological and clinical experiments demonstrate that the two main active components in ginkgo biloga extract, i.e. flavones and lactones, do not have the completely same pharmacologic actions (E. M. Middleton, A. H. Teramura, Plant Physiology, 103 (1993) 741), and the different combinations thereof in different ratios may achieve therapeutically different effects. Especially, since the research team led by P. Braquet in France firstly identified that ginkgolides had a strong and specific inhibitation for platelet activating factor (PAF) receptors, as the currently most potent PAF receptor blocker, ginkgolides has been applied in many clinical researches for the treatments of, for example, asthma, endotoxin shock, reject reaction of organ transplantation, cardiovascular and cerebrovascular diseases, various inflammatory diseases, and the like, and achieved remarkable achievements. (P. Braquet, Drug. Future, 12 (1987) 643.) Since all the above pharmacologically and pharmacodynamically intensive studies on ginkgo leaves and pharmaceutical development of ginkgo preparation require urgently testing samples only containing the single principle component, it proposes a high demand for the isolation and purification of the two active components in ginkgo leaves. At present, the separating process described in a Japanese patent (J. Oreilly, WO 9633728, 1996) is predominantly adopted, which comprises a plurality of steps including solvent extraction, decoloration with active carbon, recrystallisation, and the like. However, such process is complicated with a great loss of the active components. Especially, it uses a large amount of organic solvent with a low boiling point and strong toxicity in the isolation, resulting in serious environmental pollution. In recent years, resin adsorption method shows unique advantages in extract and separation of natural productions. For example, it has the simple process and device, less investment and high extraction yield and may greatly reduce the production cost, when compared with conventional solvent extraction. Meanwhile, as this method uses less organic solvent, e.g. only water and alcohol, and most of the alcohol can be recovered, it is an environment-friendly technology and is highly competitive at the technical level. However, the adsorption selectivity of the existing polymeric adsorbents is too bad to be used to separate the components with similar property. Therefore, a satisfied result is hard to be obtained in the isolation of active components from ginkgo leaves, and auxiliary steps such as solvent extraction, decoloration with active carbon, and the like are still needed after adsorption process. Hence, the advantages of the adsorption method do not be exhibited. (Jinyu Han, Yingchun Yan, et. al., Isolation and Purification of Terpene Lactones from Ginkgo Biloba, Chinese Traditional and Herbal Drugs, Vol. 33, (2002), issue 11).